Sealing machine and method



Aug. 12, 1952 Filed Dec. 3, 1949 1'. E. PIAZZE 2,606,850

SEALING MACHINE AND METHOD 3 Sheets-Sheet 1 INVENTOR. V

BY MQWM' VW Aug. 12, 1952 1-. E. PIAZZE SEALING MACHINE AND METHOD 3Sheets-Sheet 2 Filed Dec. 5. 1949 Aug. 12, 1952 T. E. PIAZZE SEALINGMACHINE AND METHOD 3 Sheecg-Sheet 5 Filed Dec. 5, 1949 INVENTOR. mlflaj%Patented Aug. 12, 1952 .SEALING MACHINE AND METHOD Thomas E. Pia'zze,Mount Vernon, Ohio, assignor to Shellmar Products Corporation, Chicago,111., a corporation of Delaware Application December 3, 1949, Serial No.131,030

Thi invention relates to bag closing andsealing and is more particularlyconcerned with im-: provementsin methods and mechanisms forautomatically closing the end of a bag and providing the same with atransverse seal. a J

It is a general object of the invention to provide improvements inmethods and mechanisms for conveying a bag in a predetermined path, forautomatically closing the top margins of the bag opening and forthereafter sealing the same by a transverse heat seal.

It is a more specific object of the invention to provide an improvedmethod and mechanism for heat sealing the end of a bag whichcomprisesend portions of heat scalable material, which ma terial is characterizedby its ability to melt along an edge or fold thereof when subjected toradiant heat and thereafter to cool in an integral beadlike formationalong-the melted edge or fold.

It is a further object of the invention to provide a method and machinefor heat sealing theend of a bag formation which comprises heat sealablematerial, said material being characterized by its ability, when meltedalong an edge or fold, to cool in bead-like formation along said edge orfold wherein the material at the end of the bag is brought into flatfolded relation to provide a marginal edge or fold extending in asubstantially uniform line across the bag end, the marginal edge or foldis subjected to radiant heat sufficient to melt the material along arelatively narrow end area, the melting being confined to said end areaby cooling means engaging the folded material inwardly of said area andthe melted material is thereafter cooled to form a bead-like closureseam.

It is another object of the invention to provide a'method and machinefor heat sealing the end of a'bag of the type described wherein the'bagend is brought into flat folded relation and a closure seam.

It is a further object of the invention to provide a bag sealing machinewhich comprises, in combination, a conveyor for transporting bags in agenerally horizontal path, with the top edges of the respective bagsuppermost and in closed 40 reverse fold is formed therein to providea-uni-' 10 Claims. (01. 154542) relation, a radiant heater disposedalong thepath of movement of the bag and in spaced relation to theuppermost extremities of the tops thereof for melting the material in amarginal transverse area'acros s the respective bag tops and coolingmembers engaging the bag tops in predetermined spaced relation inwardlyrelative to the uppermostedges thereof whereby to limit the area of thematerial melted and provide therein a transverse seal.

It is another objectof the invention to provide a heat sealing machinecomprising a pair of traveling cooling bands adapted to engage the topofa bag along apredetermined transverse line spaced below the uppermargins thereof and a radiant heat sealer arranged in generally parallelspaced relation above the path of travel of the cooling bands for fusingportions of the bag top extending upwardly of the cooling bands andforming therein a bead-like seal formation.

It is another object of the invention to provide in combination with aconveyor for transporting a bag with its top edges uppermost along agenerally horizontal path, a pair of generally parallel travelingcooling belts arranged in spaced relation to the conveyor and engagingthe top ofthe bag at a predetermined inwardly spaced distance from theuppermost edges thereof and a radiant heating element arranged ingenerally parallel relation with the cooling belts and spaced above theupper edges of the bag. a distance sufficient to melt the upwardlyprojecting portions of a bag top engaged by the cooling belts and formtherein a bead-like seal. a

It is another object of the invention to provide in combination with asealing machine of the type described a cutting device for trimming theupper margins of the has top to provide a uniform edge to facilitateformation of the heat seal.

It is another object of the invention to provide in combination with thesealing machine of the type described a folding device for folding overmarginal portions of a bag top to provide therein a reverse fold withthe folded edge uppermost and positioned above the uppermost edges ofthe cooling belts in the sealing machine.

It isanother object of the invention to provide in a bag sealing machineof the type described a pair of cooling belts adapted to engage the bagtop at a spaced distance below the uppermost margin thereof andresilient means for mounting one of the belts relative to the other toprovide pressure between the belt surfaces which contact V the bag top.

These and other objects of the invention will be apparent from aconsideration of the mechanisms shown by Way of example in the accompanying drawings, wherein:

Fig. 1 is a bottom plan view of a sealing machine incorporating theprinciples of the invention, with the bottom cover members removedtherefrom; I

Fig. 2 is a cross section to an enlarged scale, taken generally on theline 2-2 of Fig. 1;

Fig. 3 is a side elevation with portions thereof in section;

Fig. 4 is a transverse cross section, taken generally on the line 4-4 ofFig. 1;

Fig. 5 is a perspective view of the top of abag having a transverse sealapplied by the mechanism shown in Figs. 1 to 4;

Fig. 6 is a plan view, partially schematic, of

a modified form of the machine;

Fig. 7 is a side elevation of the machine shown in Fig. 6;

Fig. 8 is a cross section, taken generally on the line 88 of Fig. 6, toan enlarged scale;

and

Fig. 9 is a perspective view of the top of a bag incorporating thetransverse seal provided with the mechanism shown in Figs. 6 to 8.

Referring to Figs. 1 to 5 of the drawings, there is illustrated a methodand mechanism incorporating therein the principles of the inventionwherein a transverse heat seal is applied to the marginal edges of theend of a bag formation, the bag end being formed of a mater al. such asfor example, polyethylene film, which material is characterized by itsability when an edge or fold thereof is subjected to radiant heat r tomelt along the edges or fold and thereafter to cool in a bead-likeformation. The mechanism comprises a base 10 which may be a metalcasting formed in a conventional manner. The base In supports independing relation thereon a sealing mechanism H and a bag top foldingmechanism l2 which are adapted tooperate on bags l3 conveyed beneath theframe H) by an endless conveyor 14.

The conveyor (4 may be supported in any conventional manner beneath thesealing and folding mechanisms H and I2 and operated by a separatedriving mechanism (not shown) or it may be driven by the same powerdevice which operates the sealing and folding mechanism. The-conveyor itis adapted to convey the bags l3 through the folding and sealingmechanisms l2 and H with the top marginal portions l5 of thebags I3 inupstanding relation and with opposite walls thereof flattened or broughttogether on each other, either with or without a bellows fold. Intheillustrated form a bellows fold i6 is employed to reduce the lengthof the seal and facilitate the folding and sealing operations. v

The bag top folding mechanism I2 is supported partially by a pair oflaterally spaced bracket members I? and (8 which project horizontally atone end of the base H3 and are bolted or otherwise secured thereto. Theopposed edges of the brackets l1 and [8 are arranged in spaced relationto the longitudinal center lined the machine providing a slot IQ forreceiving the bag top l5. a

A pair of cooperating bag top folding members and 2! are secured to thebracket members l8 and i1, respectively. The folder member 20 comprisesa relatively long narrow vertical blade extending generally along thecenter line of the machine and an angular bracket forming horizontalportion 22 secured to the supporting bracket member [8. The foldermember 2| comprises a relatively long narrow blade portion arranged inparallel spaced relation to the blade 20 and having a reversely turnedtriangular folder portion 23 which progressively folds the upwardlyextending bag top l5 downwardly around the folder blade 2U as'the bagapproaches the sealing mechanism H. V The folder member 2| is secured tothe supporting bracket H by means of an angle plate portion 24.

Thebag top i5 is engaged and carried through the folder members 20 and2| by a pair of cooperating endless belts 25 and 28 having their innerruns in opposed relation. The belts 25 and 26 are supported on theirouter ends on pulleys 21 and 28 which are rotatably mounted on subshafts 29 and 38 depending from the bracket members I! and [8,respectively. At their inner ends the belts 25 and 26 are supported on apair of pulleys 3i and 32 which are rotatably mounted on stub shafts 33and 34 depending from the base In of the machine. The belt25 is slightlyshorter than the belt 26 to facilitate engagement with the bag top 15. Aplurality of idler pulleys 35 are arranged in back-up relation to theopposed runsof the belts 25 and 26 to hold the same in gripping relationwith the bag top I5.

The bag top 15 is delivered from the feed-in belts 25 and 26 to a pairof cooling and conveying bands 36 and 31. The cooling bands 36 and 31are supported at one end on the pulleys 3| and 32 which carry the innerend of the feedin belts 25 and 26. At the other end of the machine thebands 36 and 31 are supported on pulleys 38 and 39 which are mounted onshafts 4B and rotatably journaled in bosses 42 and 23 depending from thebase I0. The shafts and-4| extend above the upper surface of the base Inand are connected in rotatable relation by a pair of gears Hand 45. Theshaft 40 ex tends above the gear 44 to receive a driving pulley 46 whichis connected by a belt 4'! with a pulley 48 on a change-speed device 49which is driven by the motor 59. The motor 58 and accompanyingchange-speed device 49 may be supported on the'upper surface of the baseIt or on a bracket or other structure supporting the base It and anyaccompanying mechanism.

The cooling bands 36 and 37 are arranged with the opposed runs whichengage the folded bag top (5 at opposite sides and hold the same infolded relation while it is carried through the machine. The bands 36and 31 are cooled by engagement with a pair of elongate cooling members5! and 52. The cooling element 5! is supported by bolts 53 engagingbosses 54 depending from the base i0 and having a spacer member 55 toposition the cooling member 5| in proper relation to the band 38. Hoseconnections 56 are preferably provided at opposite ends of the member 5|to supply the same with a cooling fluid. The cooling member 52 isresiliently supported relative to the cooling member 5| being secured toa plate 51 which extends parallel to the base 10 beneath the same andwhich is slidably supported thereon by means of a headed bolt 58 whichis slidable in a slot 59 in a supporting plate 68 which is secured tothe base H). The plate 51 is recessed or cut away at its opposite endsand the longitudinal edges of the recessed ends are engaged bycompression springs 61 which are mounted in recesses in blocks 62. Theblocks 62 are secured in fixed relation on the; supporting plate 60.

The cooling member '52 is also preferably provided with hose connections63 at opposite ends for connecting the same to a supply of coolingliquid or other cooling medium. Other means for maintaining the coolingmembers at the desired cooling temperature may-be employed.

A radiant heating member 54 which may be an electrical resistance wire,or the like, is mounted in a longitudinally-extending recess 65 in aheat insulating block (it-which is secured by means of a bracket 67 to adepending portion 68 on the base In and extends in parallel relation tothe upper edges of the cooling bands 36 and 3! with the element 64 at apred-etermineddistance above the same. The heating-element 64 isconnected to a current supply with suitable temperature control devices.

The top edge of the bag after it is folded over by the folding mechanism[2 is carried through the machine between the cooling bands 36 and 31 inspaced relation to the heating element 64 and the uppermost edge thereofwhich extends above the bands 36 and 31 is subjected to radiant heat bythe element 64 throughout its length. The bag travels at a speed whichpermits the folded top edge to be fused or melted by the heat from theelement 64. The bag to-p material is cooled where it is contacted by thebands 36 and 3'! which limits the extent of the melted portion to arelatively narrow transversely extending area. As it passes beneath theheating element 64 the fused or melted edge forms into a bead whichcools when it progresses beyond the element 64 and forms an integralbead-like seal 69 (Fig. '5). The sealed bag is released from themachineas the top passes from between the cooling bands 36 and 3''! at thedischarge end of the. machine and is carried away by the conveyor M.

Referring to Figs. 6 to 9, there is illustrated a modified form of theinvention in which the mechanism is shown partially schematic. In thisform, a pair of metal bands .70 are arranged in parallel relation andsupported onlongitudinally spaced pairs of end pulleys H and 12 whichare mounted at opposite ends of a supporting base 13 on pairs ofdepending shafts l4 and 75, respectively. The pulleys at either end maybe driven by pow-er mechanism of the same character as shown inconnection with the preferred form of the device. The opposed inner runsof the metal bands mare guided by a plurality of pres sure rollers 1:6arranged on opposite sides of the bands along the center line of themachine.

The bags Tl to be sealed are carried on a parallel conveyor in the samemanner as in the preferred form which operates in timed relation to themovement of the bands 10. The folded or collapsed tops 18 of the bags Tlpass between the pulleys H at the receiving end of the-machine and areengaged between the opposed runs of the bands 70. 3

A pair of slitting wheels 19 and 89 are arranged above the bands 10 andspaced inwardly of the receiving end of the machine. The slitting wheels19 and 89 are mounted on shafts 8! and 82 depending fromthe base 13.They engage the bag top 18 at a predetermined spaced distance above theupper edges of the bands (0 and trim the top thereof to provide auniform top edge 33. The. waste material trimmed from the top of the bagmay be conveniently removed by a belt 84 which engages at one end in agroove 85 in the slitting wheel 19. The belt 84 engages a pulley 86depending from the base 13 and driven along 6 with the trimming wheels19 and 80 at the speed of the bands I0. As the bag top 18 moves beyondthe trimming wheels 19 and 80 it passes beneath a radiant heating device81.

The radiant heating device 81 (Fig. 8) comprises a heat resisting block88 having a longitudinal slot or groove 89 in its bottom face and'asuitable heating element 90 positioned in the groove 89 in spacedrelation above the upper edges of the bands 10.

A pair of cooling devices 9| are arranged on opposite sides of the bands10 along the radiant heating device 81 and in spaced relation below thesame. toward the other by springs 92 seated in recesses in supportingblocks 93 fixed'to the base 13; The cooling. devices 9! are providedwith hose connections 94 for supplying the same with a cooling liquid.The cooling devices 9| hold the bands 10in engagement with the top 18 ofthe bag. A relatively narrow marginal portion of the bag top 18 extendsabove the bands 10 which is fused or melted by the radiant heatingdevice 81.

As the bag 18 passes beyond the radiant heating device 81 it movesbeneath a seam cooling device 95 which isspaced sufficiently far abovethe upper edge of the bands 10 to avoid contact with the projectingmelted or fused seam forming portion 96 of the has top 18. The coolingdevice 95 may be in the form of a tank with a circulated cooling mediumof any desired character. After the bag 18 has passed beneath thecooling device 95 it is discharged from the machine as it passes betweenthe end pulleys l2.

The sealed bag 11 as shown in Fig. 9 isprovided along the upper marginof the top portion 18 with a seam 96 which is integral with the materialforming the walls of the bag and which is bead-like in formation.

In both forms of the machine which are illustrated the extent of theseam is controlled by varying the amount of material permitted to extendabove the cooling belts. The material which forms the seam is held inclosely contacting relation by the cooling belts as it, is subjected tothe radiant heat. The melting of the material to form the seam .tends'toeliminate the effect of any small particles of the contents of the bagwhich might adhere to the walls during the filling operation.

While the mechanism is particularly adapted for sealing bags formed ofpolyethylene film material, it may beused for-sealing bags of anymaterial having'similar melting or seam forming characteristics. The topof the sealed bag is provided with a transverse seam which is integralwith the bag material, which is bead-like in formation and which. is ofsubstantially uniform or-oss'secticn andfs-trength across the fullwidthof the bag top.

The mechanism may be used also to form a seal or seam on empty bags orto join the edges of two or more pieces of sheet material, the coolingbelts being adapted to convey the material along beneath the radiantheating device in proper relation to insure that the material will beproperly melted to form the bead-likeseam.

In the illustrated forms of the machine the bags or other work beingsealed are carried along with the edges of the material to be sealeduppermost, but it will be understood that the mechanism may be otherwisearranged relative to the work. It may be positioned so that the work iscarried on one side or above the mechanism. In thev latter One of thecooling devices 9| is urgedposition the mechanism would merely be in-'verted.

I claim: 4

1. In a bag top sealing machine, means for conveying a filled bag in asubstantially horizontal direction with the bag in upright position andits. open top uppermost, means for bringing opposite walls of the top ofthe bag into fiat folded relation, cooling bands mounted for. horizontalmovement and arranged to engage the bag top with a relatively narrowportion thereof projecting above the upper edges of said bands, and aradiant heating element arranged in generally parallel vertically spacedrelation to the upper edges of said bands whereby the projecting portiononly of said bag top is fused into a bead-like formation upon beingconveyed beneath said heating element,

' 2. In a bag top sealing machine, means for carrying a filled baforward in a substantially horizontal direction with the bag in uprightposition and its open top edge uppermost, means for bringing oppositeWalls of the top of the bag into flat folded relation, means for forminga transverse fold in the marginal portion of the bag top, a pair ofcooperating relatively narrow band members mounted for horizontalmovement and arranged to engage the folded portion of the bag top with arelatively small portion of the fold projecting above the upper edges ofsaid band members, and a radiant heating element ar-' ranged ingenerally parallel vertically spaced rela tion to the upper edges ofsaid band members whereby the projecting portion only of said fold isfused into a bead-like formation when said bag is carried forwardbeneath said heating element.

'3. In a bag top sealing machine, means for conveying a filled bag in asubstantially horizontal direction with the bag in upright position andits top edge uppermost, means for bringing opposite walls of the top ofthe bag into flat folded relation, means for forming a transverse foldin the marginal portion of the bag top, endless traveling metal beltsmounted for horizontal movement and arranged to engage the foldedmarginal portion of the bag top with a relatively small portion of thefold extending above the upper edges of said belts, a radiant heatingelement arranged in generally parallel vertically spaced relation to theupper edges of said belts, and means adjacent said heating element forcooling said belts whereby the portion of said fold extending above saidbelts is subjected to heat from said heating element as the bag isconveyed beneath the same.

4. A bag top sealing machine comprising means for carrying a filled bagforward in a substantially horizontal direction Withpthe bag in uprightposition and its top portion in fiattenedupstanding relation, a pair ofendless traveling bands mounted for horizontal movement and arrangedwith confronting runs engaging the bag top on opposite sides with arelatively narrow marginal area of the bag top projecting above theupper edges of said bands, resilient means for urging the confrontingruns of the bands into engage-i ment with the bag top, and a radiantheating means extending in vertically spaced relation to the upper edgesof said bands, whereby the projecting marginal portion of said bag topis fused into a bead-like formation when it is carried beneath saidheating means.

5. In a bag top sealing machine, a conveyor for carrying a filled bagalong a predetermined pathwith the bag in upright position and its topupper most, means to bring the top-marginal portions of said bag intofiat engagement, means to trim the uppermost portion of said bag topalong a uniform line extending transversely of the bag, cooling beltshaving opposed runs for engaging said bag top on opposite sides and invertically spaced relation to the upper extremity of the trimmed edge ofsaid bag top as said bag is carried along a portion of its path, and aradiant heating device arranged'alon said portion of the path of traveland in spaced relation to the upper extremity of said bag edge.

6. In a bag top sealing machine wherein a filled bag is carried in asubstantially horizontal direction with the bag in upright position andits open top uppermost, a pair of cooperating endless belts havingopposed runs thereof arranged for bringing opposite walls of the top ofthe bag into fiat folded relation, a second pair of endless bandsarranged to engage the bag top between opposed runs thereof witharelatively narrow portion of the bag top projecting above theupper edgesof said bands, cooling members resiliently engaging said second pair ofendless bands and radiant heating means for melting the projectingportion of said bag top, whereby the projecting portion only of said bagtop is fused into a bead-like formation. v

7. In a bag top sealing machine, means for conveying a filled bag in asubstantially horizontal direction with the bag in upright position andits open top uppermost, means for bringing opposite walls of the top ofthe bag into fiat folded relation, means for engaging the flattened topof the bag along a line transversely of the same to form thereon auniform marginal edge, cooling bands, means for mounting saidcoolingbands for horizontal movement into engagement. with said bag topat a predetermined distance below the top marginal edge thereof wherebya relatively narrow marginal area of said bag top projects above theupper edges of said bands, and a radiant heating element arranged ingenerally parallel vertically spaced relation to the upper edges of saidbands whereby the projecting portion only of said bag top is fused intoa bead-like formation upon being conveyed beneath said heating element.

8. In a bag top sealing machine, means for carrying a filled bag forwardin a substantially horizontal direction with the bag in upright positionand its open top uppermost, means for bringing opposite top Wallportions of the bag into fiat folded relation, means for engaging thetop portion of the bag along a line transversely of the same to form auniform top marginal edge thereon, a pair of cooperating narrow bandmembers, means mounting said band members for engagementwith the bag topalong a line below the top marginal edge with a relatively smallmarginal area of the bag projecting above the upper edges of said bandmembers, a radiant heating element, and means for mounting said heatingelement in generally parallel vertically spaced relation with the upperedges of said band members whereby the projecting portion only of saidbag top is fused into a bead-like formation when said bag is carriedforward beneath said heating element. I

9. In a bag top sealing machine, a conveyor for carrying a filled bagalong apredetermined path with the bag in upright position and its topuppermost, means to bring the top marginal portions of said'bag intofiat engagement, a

of said bag top along a uniform line extending transversely of the bag,cooling belts having opposed runs engaging said bag top on oppositesides and in spaced relation inwardly relative to the extremity of thetrimmed top of the bag as it is carried along a portion of its path, anda radiant heating device arranged along said portion of the path oftravel and in spaced "relation outwardly relative to the extremity ofthe trimmed edge of said bag top.

10. In a bag top sealing machine, means for carrying a filled bagforward in a substantially horizontal direction with the bag ingenerally upright position and its open top uppermost, meansfor bringingopposite top wall portions of the bag into flat folded relation, a pairof slitting wheels arranged to trim the top portion of the bag along aline transversely of the same to form a uniform top marginal edgethereon, a pair of relatively narrow band members, means mounting saidband members for horizontal movement into engagement with the bag topalong a narrow line spaced below the trimmed edge thereof with arelatively small marginal area of the bag pro- -jecting above said bandmembers, a radiant heating element, and means mounting said heatingelement in generally parallel vertically spaced relation with said bandmembers whereby the portion of said bag top projecting above said bandmembers is fused into a bead-like formation when said bag is carriedforward beneath said heating element.

THOMAS E. PIAZZE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Zehr Oct. 3,

1. IN A BAG TOP SEALING MACHINE, MEANS FOR CONVEYING A FILLED BAG IN ASUBSTANTIALLY HORIZONTAL DIRECTION WITH THE BAG IN UPRIGHT POSITION ANDITS OPEN TOP UPPERMOST, MEANS FOR BRINGING OPPOSITE WALLS OF THE TOP OFTHE BAG INTO FLAT FOLDED RELATION, COOLING BANDS MOUNTED FOR HORIZONTALMOVEMENT AND ARRANGED TO ENGAGE THE BAG TOP WITH A RELATIVELY NARROWPORTION THEREOF PROJECTING ABOVE THE UPPER EDGES OF SAID BANDS, AND ARADIANT HEATING ELEMENT ARRANGED IN GENERALLY PARALLEL VERTICALLY SPACEDRELATION TO THE UPPER EDGES OF SAID BANDS WHEREBY THE PROJECTING PORTIONONLY OF SAID BAG TOP IS FUSED INTO A BEAD-LIKE FORMATION UPON BEINGCONVEYED BENEATH SAID HEATING ELEMENT.